I have been running a GRC-106 for some years now at different events from my M151, I installed a MX-7777 surge suppressor and use that as a main DC disconnect and don’t know what it is in it but appears to be the mother of all MOV components.

Playing around with it on the bench found that you can’t drive beyond 30 volts thru it. Using a 10A bench supply drove 45 volts into it and it shunt regulated it down to 30 volts while dissipating over 10 Amps of current and never got warm. Being a MOV don’t see where transients will be an issue.

As far as the LSB conversion goes would think that’s a waste of time. 60 meters is USB, the MMRCG net on 40 is USB and you can work 20 and 17 meters all day long with that radio. Also cannot explain why but when running RTTY on the 7.087 net AFSK everyone appears to be using USB.

Have a filter and can do the conversion but at the end of the day use the radio as it was intended, if you want a USB/LSB go out and get a Harris Falcon or something like that or just use a modern Ham transceiver. The point, at least for me is to use the radio as it was designed, built and delivered. Also remember that the frequency display will be wrong when you change the IF filter for LSB.

This last weekend did another field event at Cape Henlopen State park, Fort Miles and did both MMRCG and M & S Net along with a bunch of Hamming up on seventeen meters with my bone stock 106

Ray F/KA3EKH

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Makes sense. Lots of good info on your website too! Thanks

Mike

-------- Original message --------

From: "B. Smith" <[email protected]>

Date: 4/22/22 3:32 PM (GMT-07:00)

To: [email protected]

Subject: Re: [MRCA] AN/GRC-106 on LSB?

The "voltage spike" mentioned below can ruin your day. It is a recommended procedure to turn off your comm and other sensitive equipment when starting or stopping. Info can be found:
http://k4che.com/M151A1-Electrical/PRCpwr.htm

On 4/22/2022 2:30 PM, KA1LHZ wrote:

Someone in the group described the GRC-106 in a shelter as sounding like a blender inside a tornado. I've used it during Field Day, as well as numerous rallys and shows. I've worked 30 countries as well as 40 states and provinces with it. I use a motorola carbon microphone element in an H-250 handset. The regular microphone sounds like you're talking with a sock in your mouth. Very few issues with it. The 3 phase (???REALLY??) cooling fan on the amplifier heat sink got stuck occasionally after sitting over the winter. I lubed it with a few drops of 5W-30 Mobil1 oil, and it hasn't stuck since. That couldn't possibly have been because the almost 50 year old lubricant turnedto sludge... I also had the power input feedthrough capacitor short due to a voltage spike from starting the truck while the radio was on. The previous owner helped me replace that. I should get out ther and blow the dust out of the transistors and get it on the air now that the snow has melted in the compound. It's fun keeping a piece of history on the air. My friend Ken W1KRT told me he saw these radios running RTTY 24/7 in SE Asia when he was there. They're capable of 1 KW output but derated so Sgt Snafu couldn't screw them up too bad when trying to get traffic out while under fire and tuning a bedspring. You can see my shelter in my USAF M-37 on my QRZ page. Hope this helps.

73

DE KA1LHZ

On 4/21/22 20:22, Mike wrote:
Thank you Steven. Your information is well received!

I don't have the -106 set just yet, but I am exploring it's capabilities before I do ever pull the trigger

Can you tell me... is there anything you dislike about the 106, or something you wish it could do but doesn't?

Basically I'm looking for any reasons why someone wouldn't want one (besides the obvious like bulk or weight)

Thanks...

Mike

KD7VRG

-------- Original message --------

From: KA1LHZ <[email protected]>

Date: 4/21/22 4:24 PM (GMT-07:00)

To: Mike <[email protected]>

Cc: [email protected]

Subject: Re: [MRCA] AN/GRC-106 on LSB?

Mike

I've been looking to do this with my GRC-106A too. There used to be someone who made the xtal filter in asia, but sadly no more. From what I gather you use a DPDT shielded relay with a 24v coil to switch the original USB xtal filter with a LSB filter. The coil is connected to the front panel switch to change when the FSK position is selected ( that's what I was told). I did find a LSB xtal filter for another radio that supposedly works with the IF frequency of the RT-834. The parts are sitting in my shelter with the radio, yet to be installed. The parts could fit in the module or nearby. Sorry to not offer more specific information. I'm still in the theoretical stage until I pull out the soldering iron. I'll look at the filter and give you more info and pics. Home with the Wuhan flu, so have lots of time to wait on SCØUT and stuff like this.

73 DE KA1LHZ

On 4/21/22 17:29, Mike wrote:
Hello,

I have a question about the GRC-106 (RT-834)

I'm led to believe this radio can be modified to work on LSB. Is it just the LSB crystal filter that
is needed? Does this ADD LSB and still retain the USB capability, or does it REPLACE the USB
with LSB?

Is there anything else that needs to be done besides installing the filter? How difficult is it to do?

Thanks...

Mike
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